Interposer having molded low CTE dielectric

ABSTRACT

A method for making an interconnection component is disclosed, including forming a plurality of metal posts extending away from a reference surface. Each post is formed having a pair of opposed end surface and an edge surface extending therebetween. A dielectric layer is formed contacting the edge surfaces and filling spaces between adjacent ones of the posts. The dielectric layer has first and second opposed surfaces adjacent the first and second end surfaces. The dielectric layer has a coefficient of thermal expansion of less than 8 ppm/° C. The interconnection component is completed such that it has no interconnects between the first and second end surfaces of the posts that extend in a lateral direction. First and second pluralities of wettable contacts are adjacent the first and second opposed surfaces. The wettable contacts are usable to bond the interconnection component to a microelectronic element or a circuit panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 13/091,800, filed Apr. 21, 2011, the disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Interconnection components, such as interposers are used in electronicassemblies to facilitate connection between components with differentconnection configurations or to provide needed spacing betweencomponents in a microelectronic assembly. Interposers can include adielectric element in the form of a sheet or layer of dielectricmaterial having numerous conductive traces extending on or within thesheet or layer. The traces can be provided in one level or in multiplelevels throughout a single dielectric layer, separated by portions ofdielectric material within the layer. The interposer can also includeconductive elements such as conductive vias extending through the layerof dielectric material to interconnect traces in different levels. Someinterposers are used as components of microelectronic assemblies.Microelectronic assemblies generally include one or more packagedmicroelectronic elements such as one or more semiconductor chips mountedon a substrate. The conductive elements of the interposer can includethe conductive traces and terminals that can be used for makingelectrical connection with a larger substrate or circuit panel in theform of a printed circuit board (“PCB”) or the like. This arrangementfacilitates electrical connections needed to achieve desiredfunctionality of the devices. The chip can be electrically connected tothe traces and hence to the terminals, so that the package can bemounted to a larger circuit panel by bonding the terminals of thecircuit panel to contact pads on the interposer. For example, someinterposers used in microelectronic packaging have terminals in the formof exposed ends of pins or posts extending through the dielectric layer.In other applications, the terminals of an interposer can be exposedpads or portions of traces formed on a redistribution layer.

Despite considerable efforts devoted in the art heretofore todevelopment of interposers and methods for fabricating such components,further improvement is desirable.

SUMMARY OF THE INVENTION

An embodiment of the present disclosure relates to a method for makingan interconnection component. The method includes forming a plurality ofsubstantially rigid solid metal posts extending away from a referencesurface. Each post is formed having a first and a second opposed endsurface and an edge surface extending between the first and second endsurfaces. Then a dielectric layer is formed contacting the edge surfacesand filling spaces between adjacent ones of the posts. The dielectriclayer has first and second opposed surfaces adjacent the first andsecond end surfaces. The dielectric layer material has a coefficient ofthermal expansion of less than 8 parts per million per degree Celsius(ppm/° C.). The method also includes completing the interconnectioncomponent such that the interconnection component has no interconnectsbetween the first and second end surfaces of the posts that extend in alateral direction. The interconnection component is further completedsuch that it has first and second pluralities of wettable contactsadjacent the first and second opposed surfaces, respectively. The firstand second wettable contacts are usable to bond the interconnectioncomponent to at least one of a microelectronic element and a circuitpanel. At least one of the first wettable contacts or the secondwettable contacts matches a spatial distribution of element contacts ata face of a microelectronic element and at least one of the firstwettable contacts or the second wettable contacts matches a spatialdistribution of circuit contacts exposed at a face of a circuit panel.

The plurality of posts can be formed such that at least some of thewettable contacts are defined by the first end surfaces or the secondend surfaces. In an embodiment, at least some of the second wettablecontacts can be on either the first or second surface of the dielectriclayer and can be connected with the second end surfaces. Such wettablecontacts can be offset along the second surface of the dielectric layerfrom the connected second end surfaces. In such an embodiment, thewettable contacts can define a first pitch and the second wettablecontacts can define a second pitch that is different from the firstpitch.

In a variation of the embodiment, the dielectric layer can be a firstdielectric layer, and the method can further include forming a seconddielectric layer along, for example, the second surface of the firstdielectric layer. The second dielectric layer can have an outsidesurface along which at least some of the second wettable contacts are,and the wettable contacts can be connected with the second end surfacesby traces formed along the second dielectric layer. The method canfurther include forming a third dielectric layer along the other surfaceof the first dielectric layer. The third dielectric layer can have anoutside surface along which at least some of the other wettable contactsare, and the wettable contacts can be connected with the respective endsurfaces by second traces formed along the second dielectric layer.

The step of forming the dielectric layer can include removing a portionof the dielectric layer to uncover at least one of the first endsurfaces or second end surfaces of the posts. The first dielectric layercan be formed from a material such as: low temperature co-fired ceramic,liquid crystal polymer, glass or high filler content epoxy, amongothers. The first dielectric layer can be formed to have a thickness ofat least 10 μm between the first and second surfaces.

The plurality of posts can be formed from materials such as: gold,copper, copper alloy, aluminum, or nickel. Further, the posts can beformed on a rigid metal layer that defines the reference surface, andthe step of completing the interconnection component can further includeselectively removing portions of the rigid metal layer to form aplurality of traces connected to at least some of the first plurality ofwettable contacts. The posts can be formed on the rigid metal layer byplating the posts along selected areas of the rigid metal layer.Alternatively, the posts and the rigid metal layer can be formed byetching a solid metal layer to remove metal from areas outside the postsso as to leave a portion of the solid metal layer to form the rigidmetal layer with the posts extending therefrom. Such a step can furtherincluding removing selected portions of the rigid metal layer to formtraces extending between at least some of the first end surfaces.

The reference surface can be defined by an inside surface of aredistribution layer, and the redistribution layer can have an outsidesurface along which at least some of the first wettable contacts areformed. The first wettable contacts can be connected to the second endsurfaces by first traces formed within the redistribution layer.

Another embodiment of the present disclosure relates to a method formaking a microelectronic assembly. The method can include mounting aninterconnection component made according to the previous embodiment to asubstrate having a plurality of first contact pads formed thereon suchthat at least some of the first wettable contacts are electricallyconnected to the first contact pads. The method can further includemounting a microelectronic element having a plurality of second contactpads formed thereon to the interconnect structure such that at leastsome of the second contact pads are electrically connected to the secondwettable contacts of the interconnect structure.

A further embodiment of the present disclosure relates to a method formaking an interconnection component. The method includes forming aredistribution layer on a carrier, the redistribution layer including aredistribution dielectric having a first surface on the carrier and asecond surface remote therefrom. A plurality of first contact pads canbe uncovered by the substrate at the first surface thereof. A pluralityof traces have portions thereof embedded within the substrate andfurther have portions thereof uncovered by the substrate at the secondsurface thereof. The method further includes forming a plurality ofsubstantially rigid solid metal posts extending away from theredistribution layer. Each of the conductive elements include a baseelectrically joined to a trace of the redistribution layer, an endsurface remote from the base, and an edge surface extending between thebase and the end surface. A dielectric material layer is then depositedalong portions of the second surface and the traces not covered by theposts and extending along the edge surfaces of the posts to an outsidesurface remote from the redistribution layer. The method is carried outsuch that the end surfaces of the posts are uncovered by the dielectricmaterial layer and such that there are no interconnects between thefirst and second end surfaces of the posts that extend in a lateraldirection.

Another embodiment of the present disclosure relates to aninterconnection component. The interconnection component includes aplurality of substantially rigid solid metal posts, each having a firstend surface, a second end surface remote from the first end surface, andan edge surface extending between the first and second end surfaces.Each post extends in a direction normal to the end surfaces, and eachpost is a single monolithic metal region throughout and at the edgesurface thereof. The component also includes a dielectric layer having acoefficient of thermal expansion of less than 8 parts per million perdegree Celsius (ppm/° C.) directly contacting the edge surfaces andfilling spaces between adjacent ones of the posts. The dielectric layerhas first and second opposed surfaces adjacent the first and second endsurfaces, the first and second surfaces extending in lateral directions.The interconnection component has no interconnects between the first andsecond end surfaces of the posts that extend in a lateral direction. Theinterconnection component has first and second pluralities of wettablecontacts adjacent the first and second opposed surfaces, respectively.The first and second wettable contacts are usable to bond theinterconnection component to at least one of a microelectronic elementand a circuit panel. At least one of the first wettable contacts or thesecond wettable contacts matches a spatial distribution of elementcontacts at a face of a microelectronic element and at least one of thefirst wettable contacts or the second wettable contacts matches aspatial distribution of circuit contacts exposed at a face of a circuitpanel.

At least some of the wettable contacts can be defined by the first endsurfaces or the second end surfaces. The posts can be made from copper.The substantially rigid solid metal posts can, also be made from gold,aluminum, or nickel. At least one of the posts can include a first endregion adjacent the first end surface and a second end region adjacentthe second end surface. Further, the at least one post can have an axisand a circumferential surface which slopes toward or away from the axisin the vertical direction along the axis such that the slope of thecircumferential wall changes abruptly at a boundary between the firstend region and the second end region. Further, the posts can formsurfaces of revolution around an axis extending between the first andsecond end surfaces. In an example, at least some of the surfaces ofrevolution can be truncated cones. Alternatively, at least some of thesurfaces of revolution can be parabolic along a portion thereof.

The first dielectric layer can be made of a material such as: lowtemperature co-fired ceramic, liquid crystal polymer, glass, and highfiller-content epoxy. The first dielectric layer can have a thickness ofat least 10 μm between the first and second surfaces. The thickness canfurther be between about 30 μm and 70 μm.

At least some of the first wettable contacts can be connected with thefirst end surfaces and are offset along the first surface of thedielectric layer from the connected first end surfaces. At least some ofthe second wettable contacts can be connected to the second end surfacesand can be offset along the second surface of the dielectric layer fromthe connected second end surfaces. The interconnection component canfurther include a plurality of first traces on the first surface of thefirst dielectric layer that are connected to at least some of the firstends of the posts.

The dielectric layer can be a first dielectric layer, and the firstwettable contacts can be exposed on an outside surface of a seconddielectric layer disposed along the first surface of the firstdielectric layer and can be connected with the first end surfaces byfirst conductive traces embedded in the second dielectric layer. Atleast some of the second wettable contacts can be offset along the firstsurface of the second dielectric layer from the connected second endsurfaces, and the second wettable contacts can be exposed on an outsidesurface of a third dielectric layer disposed along the second surface ofthe first dielectric layer. The second wettable contacts can beconnected with the second end surfaces by second conductive tracesembedded in the third dielectric layer.

The first wettable contacts can define a first pitch and the secondwettable contacts can define a second pitch that is smaller than thefirst pitch. In one variation, the second pitch can be up to 50% of thefirst pitch.

In a further embodiment of the present disclosure, a microelectronicassembly can include a microelectronic element having element contacts.The assembly can further include an interconnection component accordingone of the previously-described embodiments and a circuit having circuitcontacts thereon. At least some of the first contact pads of themicroelectronic element are bonded to the first wettable contacts of theposts of the interconnection component, and the second wettable contactsare bonded to the circuit contacts.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will be now described withreference to the appended drawings. It is appreciated that thesedrawings depict only some embodiments of the invention and are thereforenot to be considered limiting of its scope.

FIG. 1 is a top view of a structure that can be used to form part of aninterconnection device according to an embodiment of the presentdisclosure;

FIG. 2 is a side view of the structure shown in FIG. 1;

FIG. 3 is a top view of an interconnection component according to anembodiment of the present disclosure;

FIGS. 4 and 5 show an interconnection component according to anembodiment of the present disclosure during various steps of thefabrication thereof;

FIGS. 6A and 6B show variations in an interconnection component duringalternative steps of a fabrication method according to embodiments ofthe present disclosure;

FIG. 7 shows a further step in a fabrication method according to anembodiment of the present disclosure;

FIG. 8 shows an interconnection component according to an embodiment ofthe present disclosure;

FIGS. 9A and 9B show alternative embodiments of an interconnectioncomponent that include additions to the embodiment of FIG. 8;

FIGS. 10A and 10B show variations of a microelectronic assemblyrespectively including interconnection components according to theembodiments of FIGS. 8 and 9A;

FIGS. 11-13 show an interconnection component during steps of analternative fabrication process; and

FIG. 14 shows an electronic system that can include a microelectronicassembly as shown in FIGS. 10A and 10B.

Herein, identical reference numerals are used, where possible, todesignate identical elements that are common to the figures. The imagesin the drawings are simplified for illustrative purposes and are notdepicted to scale.

The appended drawings illustrate exemplary embodiments of the inventionand, as such, should not be considered as limiting the scope of theinvention that may admit to other equally effective embodiments.

DETAILED DESCRIPTION

FIGS. 4-7 show an interconnection component 2, during stages of a methodfor fabrication thereof. The interconnection component 2 is shown in acompleted form in FIG. 8 having a plurality of posts 10 within adielectric layer 20. Posts 10 have end surfaces 10A and 10B remote fromeach other with an edge surface 14 extending therebetween. End surfaces10A and 10B are left uncovered by the dielectric layer 20 oncorresponding surfaces 228 and 226 thereof. Widths of the end surfaces10A, and 10B are generally selected in a range from about 50 to 1000 μm,for example, 200-300 μm. The posts 10 can also be in the form ofconductive pins.

The posts 10 can be formed at locations facilitating connectivitybetween elements of a microelectronic assembly. Such posts may havedifferent form factors and be organized, for example, in one or moregrid-like patterns having a pitch in a range from 100 to 10000 μm (e.g.,400-650 μm).

Dielectric layer 20 extends at least partially over surface 7, which inFIG. 13 is defined by portions of traces 30 and portions ofredistribution dielectric 62. Dielectric layer 20 can be formed from,for example, compositions which cure by chemical reaction to form apolymeric dielectric, such as epoxies and polyimides may be used. Inother cases, the flowable composition can be a thermoplastic at anelevated temperature, which can harden to a solid condition by cooling.Preferably, dielectric layer 20 forms binding interfaces with featuresof the component 2, including, for example, posts 10 and traces 30. Thematerial used for dielectric layer 20 can further include one or moreadditives influencing properties of dielectric layer 20. For example,such additives can include particulate materials such as silica or otherinorganic dielectrics, or fibrous reinforcements such as short glassfibers.

Interconnection component 2 can include a dielectric layer 20 that ismade from a material having a low coefficient of thermal expansion(“CTE”). The CTE of the material used to form dielectric layer 20 can bein the range of 8 parts per million per degree Celsius (“ppm/° C.”) orlower. Components such as the interconnection component described hereinmay be subject to frequent high temperatures and cycling between highand low temperatures during manufacture, testing, or use. Inapplication, as shown in FIGS. 10A and 10B, one or more microelectronicelements having fine-pitch bonding interfaces can be flip-chip bonded toan interconnection component 2 having a lower CTE dielectric layer 20.Because the difference in the CTE between the interconnection componentand, for example, the microelectronic element 6 can be reduced to a moremanageable quantity. In such cases, reduced stress at the bondinginterface can permit reductions in solder bump sizes at the bondinginterface to help achieve finer pitch.

Moreover, when structures within an interconnection component havediffering CTEs, the different amounts by which they expand and contractdue to changing temperatures can apply stresses between the dielectriclayer 220 and posts 210 which can lead to delamination or cracking undercertain conditions. Accordingly, a component having such a dielectricmaterial layer can be less likely than components having higher CTEs tohave pins 210 become detached from within the molded dielectric layer220 during use. By forming dielectric layer 20 with a low-CTE, or onethat is closer to that of the conductive material used to form pins 10,the structures will expand and contract by closer amounts, therebypotentially reducing the likelihood of bonding interface failures.Dielectric materials that can be used to form a molded dielectric layer20 in a substrate or interconnect component as described herein caninclude various low-temperature co-fired ceramics, variousliquid-crystal polymers (“LCP”), and glass. Certain composite materialshaving an epoxy matrix can also exhibit an appropriately-low CTE. Suchmaterials include high filler content epoxy composites, wherein thefiller is formed from glass or other similar materials.

As shown in the figures, interconnection component 2 is free from anyelectrically conductive interconnects running between the posts 10 orelsewhere in an at least partially lateral direction (parallel to thesurfaces 26,28 of dielectric layer 20) within the dielectric materialbetween the end surfaces 10A and 10B. Traces 30 or the like can be usedto form connections running in a lateral direction outside of the areabetween end surfaces 10A and 10B. In an example, there are no lateralconnections within dielectric layer 20. In another example, withindielectric layer 20 the only connections formed are by posts 10 betweenthe surfaces, 26 and 28, of dielectric layer 20.

In the interconnection component of FIG. 8 end surfaces 10B can bewettable contacts used to connect posts 10 to another component usingsolder balls or other conductive materials. For example, in FIG. 10A,end surfaces 10B are used to join posts 10 to solder balls 32, whichare, in turn, joined to contacts 50 on a microelectronic element 6.Other materials can be used in place of solder balls 32 to join featuresof the components of the assembly such as tin indium or a conductivematrix. Additional, wettable metal layers or structures can be added tointerconnection component 2 that can be wettable contacts for connectionto other microelectronic components. Such wettable metal layers orstructures can be made from nickel or Ni—Au, or organic solderablepreservative (“OSP”). Structures that can be wettable contacts includeportions of traces 30 or contact pads 34 that can be patterned withtraces 30 or can overlie traces 30 or end surfaces 10A,10B. FIG. 9A, forexample shows pads 34 that can be wettable contacts on surface 26 ofdielectric layer 20 that overlie ends 10B of posts 10 and areelectrically connected therewith.

As further shown in FIG. 8, wettable contacts can be provided as pads 34electrically interconnected with end surfaces 10A through traces 30 andother electrically conductive structure, e.g., conductive vias 36. Inone example, traces 30 can electrically connect to and overlierespective end surfaces 10A and extend away therefrom in a directionparallel to surface 28 in a redistribution layer 60. Traces 30 can beused to provide a wettable contact at a laterally offset position fromthe location of end surface 10A. In the embodiment shown in FIG. 8,multiple layers of traces 30 are formed within a redistributiondielectric 62 of redistribution layer 60; however, a single layer couldbe used to achieve a desired offset configuration. The layers of tracesare separated from one another by portions of the redistributiondielectric 62 that extend between the traces 30 both in different layersand within the same layer. The traces 30 are connected, as desired,between layers using conductive vias 36, which are formed throughportions of redistribution dielectric 60. An example of an array of pads43 offset from end surfaces 10A in a redistribution layer 60 is shown ina schematic view in FIG. 3.

Traces 30 can have different widths, including widths which are smallerthan the widths of end surfaces 10A and 10B of posts 10 (as shown inFIG. 3). This facilitates fabrication of an interconnection componenthaving high routing density. Generally, the widths of traces 30 areselected in a range from about 5 to 100 μm (e.g., 20-40 μm); however,portions of traces (such as portions of traces 30 used as wettablecontacts) or some traces, themselves, can have widths greater than 100μm. Together with the posts 10, traces 30 can form an electrical circuitof interconnection component 2. Each trace 30 can be connected to atleast one post 10 or to at least one other trace. However, some tracescan “float”, in that they can be electrically disconnected from postsand other traces. Likewise, one or more of the posts can remainunconnected to any traces.

An embodiment of interconnection component 2 having one or moreredistribution layers 60 can allow interconnection component 2 to beused to connect to a microelectronic component having a differentconnection configuration than the configuration of posts 10. Inparticular, interconnection component 2 can be configured with aredistribution layer that gives an array of wettable contacts differentpitches on either side of the component. As shown in FIG. 8, the pitchof end surfaces 10A used as wettable contacts formed by on surface 26 isgreater than the pitch of the wettable contacts formed by vias 36 onsurface 64 or redistribution layer 60. The embodiment shown in FIG. 9Ais similar in this respect, in that the pitch of the wettable contactsthat are the pads 34 on surface 26 is greater than the pitch of thewettable contacts that are pads 34 on outside surface 64.

As shown in FIGS. 10A and 10B, interconnect component 2 in either of theforms shown 9 and 10A, respectively, can be used to connect twocomponents with respective contacts having different pitches or otherdifferent configurations. In the example shown in FIG. 10Amicroelectronic element 6 has contacts 50 having a smaller pitch thanthe pitch of contacts 52 on printed circuit board (“PCB”) 12. Contacts52 of PCB 12 are joined to end surfaces 10B, which act aw wettablecontacts therefor, and contacts 50 of microelectronic element 50 arejoined to vias pads 34 of interconnection component 2, which is invertedwith respect to the depiction of FIG. 8. The embodiment shown in FIG.10B is similar to that which is shown in 10A, except that pads 34 whichoverlie end surfaces 10B act as wettable contacts for attachment tocontacts 52 of PCB 12 using solder balls 32.

FIG. 9B shows an embodiment of interconnection component 2 having asecond redistribution layer 70 formed along surface 26. Redistributionlayer 70 is similar to redistribution layer 60, except that in theembodiment shown contacts 34 overlie portions of outside surface 74 andare electrically connected to conductive vias 36 that are uncovered bysurface 74. Pads 34 are connected to respective ones of end surfaces 10Bby traces 30 and additional conductive vias 36 formed withinredistribution dielectric 72. Further, pads 34 are offset from theirrespective end surfaces 10B to be useable as wettable contacts onsurface 74 a different configuration than end surfaces 10B. In theembodiment shown, the wettable contacts formed by pads 34 have a greaterpitch than end surfaces 10B, and an even greater pitch than that of thecontacts 34 on surface 64 that are useable as wettable contacts onsurface 64. Such an arrangement can be used to form pitches for wettablecontacts that differ between their respective surfaces by a factor of atleast 1.5 and, in some embodiments at least about 2. It is noted thatpads 32 can be formed overlying vias 36 on either surface 64 or 74.Alternatively, pads 34 can be connected directly to traces 30 either bya form of bonding or by being integrally formed therewith and exposed oneither of surfaces 64 and 74. The embodiment of component 2 shown inFIG. 9B can be used in an assembly for attachment between amicroelectronic element and a PCB in a similar arrangement as shown inFIGS. 10A and 10B, and can allow for an even greater difference in pitchbetween the conductive features of the microelectronic element and thePCB.

Microelectronic elements, or devices, can be mounted on the substratesusing techniques such as a ball-bonding, as shown, or using othertechniques. Similarly, such techniques may be used for connecting thesubstrates stacked on one another as additional components to theassemblies shown herein. Further examples of such assemblies are shownand described in U.S. Pat. No. 7,759,782 and in U.S. Pat. Application.Pub. No. 2010/0273293, the disclosures of which are hereby incorporatedby reference herein in their entireties. For example, an interconnectioncomponent can be disposed on and connected to a PCB that includes anelectrically conductive EMI shield. The end surfaces of the posts canthen be solder bonded to contact pads of the PCB with the EMI shieldbeing ball-bonded to a peripheral trace of the interconnection componentfor grounding to the shield Further, the interconnection componentsdiscussed herein can be interconnected to form multi-interposerassemblies. Such an assembly, can include two interconnect componentsthat overlie each other. One of the stacked interconnect components can,for example, have a recess formed in the molded dielectric layer thereofto receive, without electronic connection to, a microelectronic packagebonded to the other interconnect component.

As shown in FIG. 13, posts 10 can include edge surfaces 14 of variousconfigurations. Edge surfaces 14A are shown as extending alongsubstantially straight lines between the respective end surfaces 10A and10B. Accordingly, edge surface 14A can form a substantially cylindricalshape along an axis extending between end surfaces 10A and 10B. Edgesurfaces 14C extend between end surfaces 10A and 10B that are differentin size such that edge surface 14C forms a substantially frustoconicalshape. Alternatively, an edge surface similar to 14C extending betweendifferently-sized bases can form a surface of revolution formed by aparabola.

Edge surface 14B is formed having a first portion 14Bi and a secondportion 14Bii, such that the portion of edge surface 14B within firstportion 14Bi slopes outwardly to face surface 28. The portion of edgesurface 14B within second portion 14Bii slopes inwardly to face awayfrom surface 28 such that the slope of edge surface 14B changes abruptlyat a boundary formed between first portion 14Bi and second portion14Bii. In an embodiment, this boundary forms ridge 15 in edge surface14B, dividing first portion 14Bi from second portion 14Bii. Ridge 15, oranother abrupt transition, can be located in any one of an infinitenumber of positions between respective end surfaces 10A and 10B,including near the halfway point therebetween or closer to either of endsurface 10A or end surface 10B. By forming posts 10 with edge surfaces14B, as described, an anchoring feature, such as ridge 15 is formedtherein, which helps secure post 10 in position within dielectric layer20. Examples of conductive projections, such as posts or pins, havinganchoring features are shown and described in U.S. Patent Appln. Pub.No. 2008/0003402, the disclosure of which is incorporated herein in itsentirety. Further examples are shown and described in U.S. patentapplication Ser. No. 12/838,974, the disclosure of which is incorporatedherein in its entirety.

In a method for making interconnection component 2, as shown in FIG. 8,posts 10 can be formed on rigid metal layer 4. As shown in FIGS. 1-2,rigid metal layer can include two layers therein such as a conductivemetal layer 4 a and a barrier, or etch-stop, layer 4 b. Alternatively,rigid metal layer 4 can be in the form of a carrier layer from with thein-process component 2′ is later removed. Posts 10 can be monolithicallyformed such as by plating a conductive metal on an electrical commoninglayer that can form part of rigid metal layer 4, or by etching posts 10from a solid layer of metal 6 disposed on an etch-stop layer 4 b, asshown in FIG. 2. In embodiments where posts 10 are formed by a processsuch as half-etching or the like, end surface 10A is considered to bepresent along a theoretical plane formed along the interface betweenposts 10 and surface 7 of layer 4. FIG. 4 shows posts 10 formed on asurface 7 on layer 4, extending away therefrom; however in otherembodiments the surface 7 that posts 10 are referred to as extendingaway from can be included on any one of the aforementioned alternativestructures. Layer 4, as shown in FIGS. 4-6 can represent any of thesestructures, including such multi-layer structures as shown in FIG. 2.

In FIG. 5, dielectric layer 20 is formed over edge surfaces 14 of posts10A and over the portions of surface 7 between end surfaces 10B. In themolding process, a flowable composition is introduced in the desiredlocations and cured to form the dielectric layer. As previouslydiscussed, the composition can be essentially any material which willcure to a solid form and form a dielectric and can further be a low-CTEcurable material. During an exemplary embodiment of the moldingprocesses, the in-process component 2 can be sandwiched between a pressplate and a counter element which can be part of a molding tool. Thecounter element can be abutted against end surfaces 10B of the posts 10and the flowable molding composition can be injected or otherwiseintroduced into the space between surface 7 and counter element.

The molding composition can be injected through at least one opening, orgate, in the counter element. Slots can further be used as escapepassages for trapped air, and can also vent excess material of themolding composition. Upon completion of the molding process, the pressplate and the counter element are removed. In some instances, the endsurfaces 10B of the posts are free of molding composition at thecompletion of the molding step. In other instances, a thin film ofmolding composition can overlie end surfaces 10B of some or all of theposts 10. In such instances, the thin film can be removed by exposingsurface 26 of the molded dielectric layer to a brief plasma etching orasking process which attacks the molded dielectric. Other processes thatcan be used for exposing tips 10B of posts 10 include grinding, lappingor polishing. In yet another variant, the dielectric materialcomposition can be provided as a mass disposed on the end surfaces ofposts or on the counter element before the counter element is engagedwith the end surfaces of the posts, so that the composition is forcedinto the spaces between the posts as the posts are brought into abutmentwith the counter element.

In an alternative embodiment, the in-process component 2 can be aportion of a larger frame that incorporates a plurality of the similarstructures for the formation of in-process components. In such anembodiment, the press plate and counter element of the molding tool areextended over the entire frame. Then, during the molding process, themolding composition is introduced simultaneously into the spaces betweenthe components and counter element. After the press plate and counterelement are removed upon completion of the molding process, thecomponents can be separated (e.g., cut out) from the frame.Alternatively, such separation may occur after step the addition of padsor one or more redistribution layers.

The molding step can form the dielectric element, or dielectric layer,with a surface 26 coplanar with end surfaces 10B of the posts 2. Themolding step can also form the dielectric layer with a surface 28 inengagement with the surface 7 and, thus, coplanar with end surfaces 10Aof the posts 10.

Interconnection component 2 can be completed by forming one or moreredistribution layers, such as redistribution layer 60 along surface 28or redistribution layer 70 along surface 26, as shown in FIGS. 8 and 9B.The completion can also include the formation of pads 34 on any orsurfaces 26, 28, 64, or 74, as described above and as shown in FIG. 9A,or as otherwise desired. Redistribution layer 60, for example, can beformed including traces 30 that are formed by etching away selectedportions of layer 4 between the desired area for traces 30, as furtherdescribed with respect to FIG. 7. Conductive traces 30 can be formedfrom the, for example layers 4 a and 4 b, using an etch process. Atleast a portion of redistribution dielectric 62 can then be appliedalong surface 28 between traces 30 and, optionally, over traces 30. Thiscan form all or a part of redistribution layer 60. Further traces 30 andportions of redistribution dielectric 62 can then be formed along withconductive vias 36 to form a multilayer redistribution layer 60, aspreviously described.

Alternatively, such as in an embodiment where pins are formed on anon-conductive carrier or the like, the carrier can be removed, exposingsurface 28 and resulting in the structure of FIG. 6B. Traces 30 can thenbe formed on surface 28 such as by patterning traces 30 directly.Alternatively, traces 30 can be formed by plating or bonding a separatemetal layer to end surfaces 10A and extending along surface 28 and thenby etching the layer to remove the area between traces 30. This processcan be continued as described above, to form a multilayer redistributionlayer. As a further alternative, a redistribution layer having traces 30embedded in a redistribution dielectric can be formed separately andjoined to either of end surfaces 10A or 10B and along the respectivesurfaces 28 and 26.

In a further embodiment pins can be fabricated from a single layer ofthe principal metal (e.g., Cu and the like). Pins 10 can be formed fromthe metal using an etch process or a plating process. The dielectriclayer 20 can then be formed using the process described above inreference to FIG. 5. Then, conductive traces 30 can be formed from theremaining metal of the layer opposite the posts 10 using an etchprocess. The in-process component can be completed according to thevarious methods described above.

An alternative method for forming an interconnection component 2 isshown in FIGS. 11-13. In FIG. 11, a redistribution layer 60 is shownformed on a carrier 80. In FIG. 12 posts 10 are then formed by platingor by etching, as described above, such that end surfaces 10A overlieselected portions of traces 30 that are connected to correspondingoffset wettable surfaces, which can be for example, pads 34 uncovered byredistribution dielectric 62. In FIG. 13, dielectric layer 20 is formedover the surface 7′ of redistribution layer 30 between posts 10 andalong edge surfaces 14 of posts 10. The interconnection component 2 canthen be removed from carrier 80 or a second dielectric layer 70 or pads32 can be formed on surface 26 prior to removal from carrier 80.

The interconnection components described above can be utilized inconstruction of diverse electronic systems, as shown in FIG. 14. Forexample, a system 90 in accordance with a further embodiment of theinvention can include a microelectronic assembly 4, being a unit formedby assembly of a microelectronic element 6 with an interconnectioncomponent 2, similar to the microelectronic assembly 4 of amicroelectronic element 6 and interconnection component 2 as shown inFIG. 10A. The embodiment shown, as well as other variations of theinterconnection component or assemblies thereof, as described above canbe used in conjunction with other electronic components 92 and 94. Inthe example depicted, component 92 can be a semiconductor chip orpackage or other assembly including a semiconductor chip, whereascomponent 94 is a display screen, but any other components can be used.Of course, although only two additional components are depicted in FIG.14 for clarity of illustration, the system may include any number ofsuch components. In a further variant, any number of microelectronicassemblies including a microelectronic element and an interconnectioncomponent can be used. The microelectronic assembly and components 92and 94 are mounted in a common housing 91, schematically depicted inbroken lines, and are electrically interconnected with one another asnecessary to form the desired circuit. In the exemplary system shown,the system includes a circuit panel 96 such as a flexible printedcircuit board, and the circuit panel includes numerous conductors 98, ofwhich only one is depicted in FIG. 14, interconnecting the componentswith one another. However, this is merely exemplary; any suitablestructure for making electrical connections can be used, including anumber of traces that can be connected to or integral with contact padsor the like. Further, circuit panel 96 can be of a similar structure toPCB having contacts 52 thereon, and can connect to interconnectioncomponent 2 using solder balls 32 or the like. The housing 91 isdepicted as a portable housing of the type usable, for example, in acellular telephone or personal digital assistant, and screen 94 isexposed at the surface of the housing. Where structure 90 includes alight-sensitive element such as an imaging chip, a lens 99 or otheroptical device also may be provided for routing light to the structure.Again, the simplified system 90 shown in FIG. 14 is merely exemplary;other systems, including systems commonly regarded as fixed structures,such as desktop computers, routers and the like, can be made using thestructures discussed above.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

The invention claimed is:
 1. A method for making an interconnectioncomponent, comprising: providing an element having a plurality ofsubstantially rigid solid metal posts extending away from a referencesurface, each post having a first and a second opposed end surface andan edge surface extending between the first and second end surfaces,each post having a single monolithic metal region throughout and at theedge surface; then forming a dielectric layer having a coefficient ofthermal expansion of less than 8 parts per million per degree Celsius(ppm/° C.) contacting the edge surfaces and filling spaces betweenadjacent ones of the posts, the dielectric layer having first and secondoutermost opposed surfaces which are coplanar with the first and secondend surfaces, respectively; and completing the interconnectioncomponent, the interconnection component having no electricallyconductive interconnects between the first and second end surfaces ofthe posts that extend in a lateral direction between the posts, theinterconnection component having first and second pluralities ofwettable contacts adjacent the first and second opposed surfaces,respectively, the first and second wettable contacts being usable tobond the interconnection component to at least one of a microelectronicelement or a circuit panel, at least one of the first wettable contactsor the second wettable contacts configured for bonding to elementcontacts on a face of a microelectronic element and at least one of thefirst wettable contacts or the second wettable contacts configured forbonding to circuit contacts on a face of a circuit panel.
 2. The methodof claim 1, wherein at least some of the wettable contacts are definedby the first end surfaces or the second end surfaces.
 3. The method ofclaim 1, wherein the step of forming the dielectric layer furtherincludes removing a portion of the dielectric layer to uncover at leastone of the first end surfaces or second end surfaces of the posts. 4.The method of claim 1, wherein the first dielectric layer is formed froma material selected from the group consisting of: low temperatureco-fired ceramic, liquid crystal polymer, glass, and high filler contentepoxy.
 5. The method of claim 1, wherein the plurality of posts areformed from at least one of the group consisting of: gold, copper,copper alloy, aluminum, and nickel.
 6. The method of claim 1, whereinthe first dielectric layer has a thickness of at least 10 μm between thefirst and second surfaces.
 7. The method of claim 1, wherein the step ofcompleting the interconnection component includes forming conductiveelements, including at least some of the second wettable contacts inelectrical connection with the second end surfaces, wherein at leastsome of the second wettable contacts are offset along the second surfaceof the dielectric layer from the connected second end surfaces.
 8. Themethod of claim 7, wherein the first wettable contacts define a firstpitch and wherein the second wettable contacts define a second pitchthat is different from the first pitch.
 9. The method of claim 7,wherein the dielectric layer is a first dielectric layer, and the stepof completing the interconnection component includes forming a seconddielectric layer along the second outermost surface of the firstdielectric layer, the second dielectric layer having a surface on whichat least some of the second wettable contacts are, wherein the secondwettable contacts are electrically connected with the second endsurfaces through first traces extending along the second dielectriclayer.
 10. The method of claim 9, wherein the step of completing theinterconnection component includes forming a third dielectric layeralong the first outermost surface of the first dielectric layer, thethird dielectric layer having a surface on which at least some of thefirst wettable contacts are, wherein the first wettable contacts areelectrically connected with the first end surfaces through second tracesextending along the third dielectric layer.
 11. The method of claim 1,wherein the step of providing the element includes forming the posts ona metal layer that defines the reference surface, the step of completingthe interconnection component further including selectively removingportions of the metal layer to form a plurality of traces extending fromthe posts at the first end surfaces.
 12. The method of claim 11, whereinthe forming of the posts includes plating the posts along selected areasof the metal layer.
 13. The method of claim 1, wherein the step ofproviding the element includes forming the posts by etching a metallayer to remove metal from areas outside the posts, so as to leave athinned portion thereof, the step of completing the interconnectioncomponent further including selectively removing portions of the thinnedportion of the metal layer to form a plurality of traces extending fromthe posts at the first end surfaces.
 14. The method of claim 11, whereinthe step of selectively removing portions of the metal layer forms atleast some of the traces extending between at least some of the posts atthe first end surfaces.
 15. The method of claim 1, wherein the referencesurface is defined by an inside surface of a redistribution dielectric,the redistribution dielectric having an outside surface on which atleast some of the first wettable contacts are, wherein the firstwettable contacts are electrically connected with the second endsurfaces through first traces extending along the redistributiondielectric.
 16. A method for making a microelectronic assembly,including: mounting a interconnection component made according to claim1 to a substrate having a plurality of first contacts thereon such thatat least some of the first wettable contacts are electrically connectedwith the first contacts; and mounting a microelectronic element having aplurality of second contacts at a face thereof to the interconnectioncomponent such that at least some of the second contacts areelectrically connected with the second wettable contacts of theinterconnection component.
 17. The method of claim 16, wherein the stepof mounting the microelectronic element includes joining the secondcontacts with the second wettable contacts through masses of conductivebonding material.
 18. The method of claim 17, wherein the step ofmounting the interconnection component with the substrate includesjoining the first contacts with the first wettable contacts throughmasses of conductive bonding material.
 19. A method for making amicroelectronic interconnection component, comprising: forming aredistribution layer on a carrier, the redistribution layer including aredistribution dielectric having a first surface on the carrier and asecond surface remote therefrom, a plurality of conductive firstconnection elements uncovered by the redistribution dielectric at thefirst surface, and a plurality of conductive traces extending along theredistribution dielectric having portions thereof uncovered by theredistribution dielectric at the second surface thereof; forming aplurality of substantially rigid solid metal posts from at least one ofthe group consisting of: gold, copper, copper alloy, aluminum, andnickel, each post extending away from the redistribution layer, each ofthe posts including a base having a first end surface, at least some ofthe posts being electrically connected with respective traces of theredistribution layer, the posts having a second end surface remote fromthe first end surface, and edge surfaces extending between the first andsecond end surfaces; and then forming a dielectric layer overlying theredistribution layer and filling spaces between the posts so that afirst outermost surface and an opposed second outermost surface of thedielectric layer are coplanar with respective first and second opposedend surfaces of the rigid solid metal posts, and the interconnectioncomponent having a plurality of wettable contacts at a surface of thedielectric layer, the wettable contacts being usable to bond theinterconnection component to at least one of a microelectronic elementor a circuit panel, and wherein the interconnection component does nothave any interconnects between the first and second end surfaces of theposts that extend in a lateral direction.
 20. A method for making aninterconnection component, comprising: providing an element having aplurality of substantially rigid solid metal posts extending away from areference surface, each post having a first and a second opposed endsurface and an edge surface extending between the first and second endsurfaces, each post having a single monolithic metal region throughoutand at the edge surface; then forming a dielectric layer having acoefficient of thermal expansion of less than 8 parts per million perdegree Celsius (ppm/° C.) contacting the edge surfaces and fillingspaces between adjacent ones of the posts, the dielectric layer havingfirst and second outermost opposed surfaces which are coplanar with thefirst and second end surfaces, respectively, wherein the firstdielectric layer has a thickness of at least 10 μm between the first andsecond surfaces; and completing the interconnection component, theinterconnection component having no electrically conductiveinterconnects between the first and second end surfaces of the poststhat extend in a lateral direction between the posts, theinterconnection component having first and second pluralities ofwettable contacts adjacent the first and second opposed surfaces,respectively, the first and second wettable contacts being usable tobond the interconnection component to at least one of a microelectronicelement or a circuit panel, at least one of the first wettable contactsor the second wettable contacts configured for bonding to elementcontacts on a face of a microelectronic element and at least one of thefirst wettable contacts or the second wettable contacts configured forbonding to circuit contacts on a face of a circuit panel, wherein theplurality of posts are formed from at least one of the group consistingof: gold, copper, copper alloy, aluminum, and nickel.